Hello all,

i am working on a 2D flow and transport model. I have set different recharge zones throughout the model's surface by using the [b] (flow) Source/Sink parameter.[/b] Then, considering the water flow input in each element, I have created a "User Data" parameter, that represents the [b]concentration[/b] of the water entering the model at each element. Finally, to calculate the total mass that enters the model at each element I have used the expression editor to assign the result of the [b]product[/b] of the [b](flow) Source/sink[/b] value times the [b]concentration[/b] to the [b](mass) Source/sink[/b] property.

At this point, I wonder if there is a more straightforward way to create this BC.

The problem I have is that I would like to calibrate the value of the Concentration, but in PEST it has no effect, as I understand that the expression used for the [b](mass) Source/sink[/b] is not "linked" and it doesn't change automatically when one changes the value of Concentration.

To clarify, I have around 20 different zones for [b](flow) Source/sink[/b], 5 for [b]Concentration[/b] and it results on more than 70 different values of [b](mass)Source/sink[/b], so It is very time consuming to do manually.

Thank you very much,